package com.xuegao.xuegaololskills;

import javax.swing.*;
import java.awt.*;
import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;
import java.text.SimpleDateFormat;
import java.util.Date;

public class NowTime extends JFrame {
    //添加 显示时间的JLabel
    public NowTime() {
        JLabel time = new JLabel();
        add(time);
        this.setTimer(time);
    }


    //设置Timer 1000ms实现一次动作 实际是一个线程   
    private void setTimer(JLabel time) {
        final JLabel varTime = time;
        Timer timeAction = new Timer(1000, new ActionListener() {

            @Override
            public void actionPerformed(ActionEvent e) {
                long timemillis = System.currentTimeMillis();
                //转换日期显示格式   
                SimpleDateFormat df = new SimpleDateFormat("yyyy-MM-dd HH:mm:ss");
                varTime.setText(df.format(new Date(timemillis)));
            }
        });
        timeAction.start();
    }

    //运行方法
    public static void main(String[] args) {
        NowTime timeFrame = new NowTime();
        timeFrame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
        timeFrame.setSize(160, 80);

        timeFrame.setLocation((int) (Toolkit.getDefaultToolkit().getScreenSize().getWidth() - timeFrame.getWidth()) / 2,

                (int) (Toolkit.getDefaultToolkit().getScreenSize().getHeight() - timeFrame.getHeight()) / 2);//居中显示窗体
        timeFrame.setVisible(true);

    }
}